During operation of an aeronautical vehicle, air is induced into an engine and, when mixed with a combustible fuel, is used to generate energy to propel the vehicle. The induced air may contain undesirable particles, such as sand and dust, which can degrade engine components. In order to prevent or at least minimize such degradation, many aeronautical vehicles use an inlet particle separator system, disposed upstream of the engine, to remove at least a portion of the undesirable particles.
A conventional inlet particle separator typically includes a duct system having a fluid passageway that transitions into a scavenge flow path and an engine flow path. Air that is induced into the fluid passageway may have particles suspended therein. The inertia of relatively larger ones of the suspended particles tends to cause these particles to travel in a straight line rather than follow the fluid passageway. Because of the manner in which the inlet particle separator is configured, most of the suspended particles tend to flow into the scavenge flow path rather curve into the engine flow path. As such, relatively clean air is directed into the engine, and contaminated air, which has the particles suspended therein, is directed through the scavenge flow path and is discharged.
Conventional inlet particle separators, such as those described above, operate at relatively high efficiencies for relatively large particles (e.g., >80 microns). However, for relatively small particles (e.g., <80 microns), the efficiencies can be relatively low, resulting in a significant amount of these relatively small particles being ingested into the engine. These relatively small particles, while being potentially less troublesome than the relatively large particles, can still have some deleterious effects. For example, these particles can plug secondary flow lines and/or can melt and form glass on relatively hot engine components, such as the combustor, which can significantly reduce engine performance or have other undesirable effects.
Hence, there is a need for an inlet particle separator system that increases the separation efficiency of relatively small particles from engine inlet air without increasing core pressure loss. The present invention addresses at least this need.